Benefits of Vitamin D3

Updated: March 27, 2024

woman getting vitamin d3 from the sun

Your Body has 30 Trillion Cells. They ALL Need Vitamin D.

That’s right. Every cell in your body benefits from Vitamin D. That’s because at the core of each of those 30 trillion cells is a vitamin D receptor. That’s important because these receptors act as switches that trigger vital functions such as immune strength, bone health, mood balance and more. And Vitamin D is the ONLY thing that can activate these switches

In fact, without a steady supply of this essential nutrient, these functions will slow down, waver, and eventually cease to operate effectively. That’s why your body’s well-being hinges on vitamin D. 

But unfortunately, 35% – 50% of Americans have a vitamin D deficiency. [1][2].

And here’s why that’s a problem…

All The Important Benefits of Vitamin D

benefits of vitamin d3

Bone Health

Vitamin D is essential for strong and healthy bones because it helps your body take in calcium. No matter how much calcium you consume from food or supplements, you need vitamin D to absorb it properly. That’s why if you don’t have enough vitamin D, you’re more likely to develop bone problems like osteopenia and osteoporosis. [3].

Cardiovascular Health

There’s ongoing research about vitamin D’s role in heart disease prevention. What we do know is that vitamin D is important for heart health. 

For instance, it helps regulate blood pressure by affecting the renin-angiotensin-aldosterone system.[4].

Vitamin D increases the production of renin, an enzyme that controls how much blood flows through your veins and arteries and manages how much your arteries tighten or relax. If renin levels are off, it can lead to too much fluid and tightness in your arteries, causing high blood pressure.[5]. 

Additionally, studies suggest that vitamin D is beneficial for maintaining healthy levels of blood lipids. This includes keeping HDL, LDL, and triglycerides at normal levels.[6].

Blood Sugar Levels

Vitamin D plays a vital role in how your body metabolizes glucose via its relationship with the hormone insulin. In your pancreas, vitamin D stimulates the release of insulin via its receptor on pancreatic beta cells. Insulin then goes on to help clear your blood of excess glucose, allowing you to maintain healthy blood sugar levels [7]. 

Your liver and muscle cells also have vitamin D receptors, which assist in peripheral insulin activity, further supporting healthy blood glucose [8].


If you find yourself getting sick more often in winter, it might be because of low vitamin D levels. Vitamin D plays a key role in your body’s immune system in two main ways:

Innate Immunity: This is your body’s first line of defense against germs like bacteria and viruses. Vitamin D helps manage your body’s inflammatory response, which is crucial when fighting off these invaders.[9]. 

Adaptive Immunity: This is the second stage of your immune response, which targets specific threats more precisely. Unlike innate immunity that reacts generally, adaptive immunity targets specific invaders. Vitamin D influences this process too, as it works on T cells, B cells, and antibodies. It helps regulate these immune cells, ensuring that this targeted immune response works effectively.[10][11].

Cognitive Health

The precise role that vitamin D plays in cognitive health has yet to be established. However, research shows that this vitamin may have both neurotrophic and neuroprotective roles in your brain – assisting with the healthy growth and protection of brain and nervous system tissue [12]. 

In animal trials, vitamin D has been shown to reduce neurotoxicity and neuronal injury, which gives us some insight into the important role this nutrient may play in the human brain [13]. 

Also, there’s some evidence that having enough vitamin D might help maintain good brain function as we get older. This is thought to be because vitamin D can support neuroplasticity, which is the brain’s ability to adapt and form new connections. [14][15].

Targeted Benefits For Men and Women

In addition to the above benefits of vitamin D, this nutrient also has some targeted benefits for both men and women.

Vitamin D Benefits for Men

Research indicates that vitamin D plays a role in men’s reproductive health, particularly in boosting testosterone levels, especially in overweight men.[16].

Beyond affecting testosterone, vitamin D might also be involved in addressing erectile dysfunction. This could be because of how vitamin D contributes to the development of the penis, its role in aiding blood flow through nitric oxide and vessel widening, and its effects on male sex hormones.[17].

Vitamin D Benefits for Women

One of the common side effects that come with aging for women is vaginal dryness. Studies show that vitamin D, taken orally or as a suppository, may enhance female lubrication and reduce atrophy during menopause [18][19].

running in the sun

Are You Getting Enough Vitamin D?

As mentioned, a large portion of the US adult population is either low or deficient in vitamin D. While nutrient deficiencies in the US are rare due to a robust food supply and widespread fortification, vitamin D is an exception to the rule because most of our vitamin D synthesis happens via sunlight. 

That means that you could be following the cleanest, most nutrient-dense, organic, local, diverse diet on the planet—and still be low in this critical vitamin

Unless you consistently spend time outdoors with a good portion of your skin exposed, it’s likely that your vitamin D levels aren’t where they should be. And since vitamin D deficiency won’t cause obvious symptoms at first, it can go undetected for years. 

So, are you getting enough vitamin D? The best way to know is to test your vitamin D levels, which can be accomplished with a simple blood test ordered by your doctor.

Tips To Boost Your Vitamin D Levels

If you know or suspect that you are low in vitamin D, there are a handful of ways to boost your levels so you can get back to optimal health.

More Sunlight

First, try to find ways to get more sunlight in your life. This could be as simple as taking a 20-minute walk during your lunch break or scheduling outdoor activities during your time off.

Vitamin D Rich Foods

Although diet is not the most effective way to increase vitamin D, you can find this nutrient in a handful of foods. Increasing your intake of foods like salmon, cod, sardines, eggs, and mushrooms may give you a little edge on your vitamin D stores – it certainly can’t hurt.

Vitamin D Supplements

If you really want to boost your vitamin D levels quickly, supplementing is the best way to do it. While sunlight can be an effective way to get more vitamin D, the sun isn’t always available to everyone, and depending on where you live, your UV exposure may not be sufficient to even make a dent in your vitamin D synthesis. 

This is why vitamin D supplements are more than a backup plan; they’ve become essential for most people living in the modern world. 

But not just any supplement will do; you’ll want to ensure that your vitamin D is both high-quality and supplying an adequate dose. For a high-quality vitamin D, ensure you’re getting it in the D3 form, not D2. While many companies add vitamin D2 to their products, D3 has superior bioavailability (it’s absorbed better) and, therefore, can boost your vitamin D levels much faster than a D2 supplement.

bottle of vitamin d3 complete


Beyond its critical role in bone health, vitamin D impacts almost every system in your body. 

This is why supplementing with vitamin D is essential for most people, even those with a well-balanced diet. 

For more information on healthy living and to stay up to date on the current research, sign up for the AlgaeCal Newsletter.


What are the vitamin D benefits for men?

Studies show that vitamin D may specifically benefit men by supporting testosterone production and assisting in erectile dysfunction.

What are the vitamin D benefits for women?

Vitamin D may support vaginal health in menopausal women by reducing vaginal dryness and preventing vaginal atrophy.

What are the five benefits of vitamin D?

Vitamin D plays a role in various physiological systems with positive impacts on bone health, heart health, immunity, cognitive function, and blood sugar.

How do you get enough vitamin D?

There are several ways to enhance your vitamin D stores. First, try to increase your exposure to sunlight, and second, try adding in more foods that contain vitamin D. For a more definitive approach, take a high-quality vitamin D supplement to ensure you get enough of this crucial nutrient each day.

Article Sources

  2. Amrein, K., Scherkl, M., Hoffmann, M., Neuwersch-Sommeregger, S., Köstenberger, M., Tmava Berisha, A., ... & Malle, O. (2020). Vitamin D deficiency 2.0: an update on the current status worldwide. European journal of clinical nutrition, 74(11), 1498-1513.
  3. Lips, P., & Van Schoor, N. M. (2011). The effect of vitamin D on bone and osteoporosis. Best practice & research Clinical endocrinology & metabolism, 25(4), 585-591.
  4. Ajabshir, S., Asif, A., & Nayer, A. (2014). The effects of vitamin D on the renin-angiotensin system. Journal of nephropathology, 3(2), 41.
  5. Forman, J. P., Giovannucci, E., Holmes, M. D., Bischoff-Ferrari, H. A., Tworoger, S. S., Willett, W. C., & Curhan, G. C. (2007). Plasma 25-hydroxyvitamin D levels and risk of incident hypertension. Hypertension, 49(5), 1063-1069.
  6. Surdu, A. M., Pînzariu, O., Ciobanu, D. M., Negru, A. G., Căinap, S. S., Lazea, C., ... & Cismaru, G. (2021). Vitamin D and its role in the lipid metabolism and the development of atherosclerosis. Biomedicines, 9(2), 172.
  7. Li, X., Liu, Y., Zheng, Y., Wang, P., & Zhang, Y. (2018). The effect of vitamin D supplementation on glycemic control in type 2 diabetes patients: a systematic review and meta-analysis. Nutrients, 10(3), 375.
  9. Wu, Z., Liu, D., & Deng, F. (2022). The role of vitamin D in immune system and inflammatory bowel disease. Journal of Inflammation Research, 3167-3185.
  11. Aranow, C. (2011). Vitamin D and the immune system. Journal of investigative medicine, 59(6), 881-886.
  12. Groves, N. J., McGrath, J. J., & Burne, T. H. (2014). Vitamin D as a neurosteroid affecting the developing and adult brain. Annual review of nutrition, 34, 117-141.
  13. AlJohri, R., AlOkail, M., & Haq, S. H. (2019). Neuroprotective role of vitamin D in primary neuronal cortical culture. Eneurologicalsci, 14, 43-48.
  14. Jia, J., Hu, J., Huo, X., Miao, R., Zhang, Y., & Ma, F. (2019). Effects of vitamin D supplementation on cognitive function and blood Aβ-related biomarkers in older adults with Alzheimer’s disease: a randomised, double-blind, placebo-controlled trial. Journal of Neurology, Neurosurgery & Psychiatry, 90(12), 1347-1352.
  15. Mayne, P. E., & Burne, T. H. (2019). Vitamin D in synaptic plasticity, cognitive function, and neuropsychiatric illness. Trends in neurosciences, 42(4), 293-306.
  16. Pilz, S., Frisch, S., Koertke, H., Kuhn, J., Dreier, J., Obermayer-Pietsch, B., ... & Zittermann, A. (2011). Effect of vitamin D supplementation on testosterone levels in men. Hormone and Metabolic Research, 43(03), 223-225.
  17. Canguven, O., & Al Malki, A. H. (2021). Vitamin D and male erectile function: an updated review. The world journal of men's health, 39(1), 31.
  18. Rad, P., Tadayon, M., Abbaspour, M., Latifi, S. M., Rashidi, I., & Delaviz, H. (2015). The effect of vitamin D on vaginal atrophy in postmenopausal women. Iranian journal of nursing and midwifery research, 20(2), 211.
  19. Kamronrithisorn, T., Manonai, J., Vallibhakara, S. A. O., Sophonsritsuk, A., & Vallibhakara, O. (2020). Effect of vitamin D supplement on vulvovaginal atrophy of the menopause. Nutrients, 12(9), 2876.

Article Comments

Add New Comment

Your email address will not be published. Required fields are marked *

  1. Danuta

    February 4, 2024 , 5:03 am

    How much vitamin D3 should I take it

  2. Yoori AlgaeCal

    February 5, 2024 , 6:26 pm

    Great question, Danuta! The amount of vitamin D a person needs depends on their vitamin D blood level. If you haven’t tested your vitamin D blood level recently, we suggest asking your doctor to order you a vitamin D blood test! We recommend discussing the optimal dose of vitamin D with your doctor based on your blood level and health goals :).

    If your test shows low levels of vitamin D, to achieve higher levels, our suggested approach is to take anywhere from 2000-5000 IU D3/day from all sources for 3-4 months and then retest your levels.

    If your test shows healthy levels of vitamin D, researchers suggest aiming for anywhere between 600-4000 IU of D3/day from all sources. It’s suggested to retest your levels in 3-4 months to see if you’re maintaining optimal levels. Of course, we recommend discussing the optimal dose of vitamin D with your doctor, as we are not medical professionals. I hope this helps!

    – Yoori

  3. Natalia Santos

    February 4, 2024 , 6:13 am

    Very interesting. Buy , how much is the maximum of IU for vitamin D3 ?

    And side effects in consuming too much of D3?

  4. Yoori AlgaeCal

    February 5, 2024 , 6:30 pm

    Thank you for reaching out, Natalia! My understanding is that the upper limit of vitamin D is, 4000IU per day. Although the established upper limit for vitamin D is 4000 IU / day, toxicity typically happens with much higher intakes of over 10,000 IU / day. Vitamin D toxicity can lead to health problems such as hypercalceria, which means you will urinate calcium and lose calcium. For more details, please visit our blog article HERE and scroll down to “Vitamin D Toxicity.” I hope this helps!

    – Yoori

  5. Marci Garton

    February 4, 2024 , 6:25 am

    good article but it didn’t mention the RDM of vit. D3 we need, specifically for me, a +70 yr old woman. Help, & thank you!

  6. Lena

    February 4, 2024 , 7:07 am

    I take 4000 units of vit d3 super k and Homestyine. Under Md and intregative dr

  7. Yoori AlgaeCal

    February 5, 2024 , 6:31 pm

    We are happy to hear that you are taking a vitamin D supplement under the guidance of your doctor, Lena! 🙂

    – Yoori

  8. Barbara Snow

    February 4, 2024 , 9:30 pm

    I was told had too much vitamin D3 in my blood. Please tell me if it’s true that too much vitamin D is dangerous to my health and why

  9. Yoori AlgaeCal

    February 5, 2024 , 6:21 pm

    Thank you for reaching out, Barbara! If your vitamin D blood level is just a bit over the normal range, not to worry too much. However, excessive levels can lead to health issues, and we recommend consulting your doctor on their best advice as we are not medical professionals. For more details, please visit our blog article HERE and scroll down to the section “Vitamin D Toxicity.” Please let us know if you have any follow-up questions!

    – Yoori

  10. Becky Ledford

    February 5, 2024 , 8:13 am

    It seems as though every vitamin is including vitamin D. Can you get too much? Should I keep a watch on how much I am getting?

  11. Myriam Radia

    February 5, 2024 , 1:21 pm

    This is a good basic article about vitamin D. However, it does not specify how much vitamin D we should take as a daily supplement. So the article isn’t that helpful.

  12. Yoori AlgaeCal

    February 5, 2024 , 6:16 pm

    We truly appreciate your feedback, Myriam! The amount of vitamin D an individual needs depend on their vitamin D blood level and health goals. We recommend checking your vitamin D blood level with your doctor.

    If your test shows low levels of vitamin D, to achieve higher levels, our suggested approach is to take anywhere from 2000-5000 IU D3/day from all sources for 3-4 months and then retest your levels.

    If your test shows healthy levels of vitamin D, researchers suggest aiming for anywhere between 600-4000 IU of D3/day from all sources. It’s suggested to retest your levels in 3-4 months to see if you’re maintaining optimal levels. Of course, we recommend discussing the optimal dose of vitamin D with your doctor, as we are not medical professionals.

    I hope this information helps, Myriam! 🙂 If you have any further questions, please give us a call at 1-800-820-0184 (US & Canada Toll-free) or email [email protected]. We are happy to help!

    – Yoori

  13. rosemarie rossi

    February 7, 2024 , 4:36 am

    is the vit d in algaecal plus d3?

  14. Barb Snow

    March 11, 2024 , 12:12 pm

    What are the parathyroid functions and connection to bone health. I have a girlfriend who got 3of her parathyroids removed to counter severe osteoporosis. It will take time to find out if it was effective. Please comment.

  15. Yoori AlgaeCal

    March 11, 2024 , 3:34 pm

    Great question, Barb! While I’m not a medical professional, my understanding is that the primary function of parathyroid glands is to regulate calcium levels in the body. It enhances calcium absorption, and stimulates vitamin D production. We are happy to hear that your girlfriend is working with her doctor to address her health concerns, and we wish her all the best! If you have any further questions, please don’t hesitate to give us a call at 1-800-820-0184 (US & Canada Toll-free) or email [email protected]. We are happy to help :).

    – Yoori

  16. freddie weber

    May 28, 2024 , 9:58 pm

    Dr says I have too much potassium & to cut down calcium products & food w potassium. Does this mean I can’t take algaecal? I just ordered it. Freddie womam

  17. Manja AlgaeCal

    May 29, 2024 , 9:32 am

    Hi Freddie, thank you for reaching out. While AlgaeCal is a calcium supplement, it’s best to discuss your specific situation with your healthcare provider. They can provide personalized advice based on your medical history and current health needs.

    To assist you in this conversation, we’ve prepared an information sheet for healthcare providers. You can find it HERE. Feel free to share this with your doctor to help guide your discussion.

    If you have any further questions or concerns, please don’t hesitate to reach out to us at [email protected] or call our Bone Health Consultants at 1-800-820-0184 (USA & Canada toll-free). We’re here to support you on your health journey!
    – Manja

This article features advice from our industry experts to give you the best possible info through cutting-edge research.

Lara Pizzorno
MDiv, MA, LMT - Best-selling author of Healthy Bones Healthy You! and Your Bones; Editor of Longevity Medicine Review, and Senior Medical Editor for Integrative Medicine Advisors.,
Dr. Liz Lipski
PhD, CNS, FACN, IFMP, BCHN, LDN - Professor and Director of Academic Development, Nutrition programs in Clinical Nutrition at Maryland University of Integrative Health.,
Dr. Loren Fishman
MD, B.Phil.,(oxon.) - Medical Director of Manhattan Physical Medicine & Rehabilitation and Founder of the Yoga Injury Prevention Website.,
Prof. Didier Hans
PHD, MBA - Head of Research & Development Center of Bone Diseases, Lausanne University Hospital CHUV, Switzerland,